1. Field of the Invention
The present invention relates to broadcast receivers and methods and apparatuses for computing viewing/listening-related information such as so-called audience ratings.
2. Description of the Related Art
When broadcasting to the general public, various methods have been employed to survey program reception states of viewers and/or listeners (recipients) at receivers (receiving terminals). Because the receivers are not provided with transmitting functions, the viewers/listeners (hereinafter referred to as “audience members”) are requested to give feedback on their program reception states via postcards, facsimiles, etc. Another example includes a method of installing back-channel transmitting devices on the receivers of some of the audience members and obtaining the program reception states of the receivers through a telephone line.
The method of requesting that the audience members to feedback their program reception states by postcards and facsimiles imposes heavy burden on the audience members, resulting in poor response rate. Even if responses are collected from the audience members, whether or not the audience members have actually seen a particular program depends on the audience members' responses, and the survey result lacks accuracy.
The method of installing the back-channel transmitting devices on the receivers of some of the audience members has a demerit in that it is impossible to install back-channel transmitting devices on small receivers such as portable receivers. Another demerit is that dedicated equipment is required for this method, leading to rising costs. It is therefore impossible to detect the program reception states of a large number of audience.